1. Field of the Invention
The present invention relates to a method of restoring cultural inheritances made of paper, and more particularly, to a method of restoring damaged portions of antique documents made of Japanese paper and machine-made paper, drawings, Japanese books, sutras, rolls, paintings, posters, etc. These works are hereinafter referred to as Japanese paper paintings and calligraphic works, or machine-made paper paintings and calligraphic works, or merely as paper paintings and calligraphic works, depending on the kinds of materials of which they are made.
Japanese paper, as used herein, means a hand-made paper, which is made from skin fibers of species such as Broussonetia kazinoki, Edgeworthia papiryfera, Wikstroemia sikokania, or the like. Machine-made paper, as used herein, means paper made from wood pulp, straw, cloth, or the like, or combinations thereof. Fibers of these materials are usually extracted from plants by mechanical or chemical methods.
2. Prior Art
The restoration of Japanese paper and machine-made paper antique documents and paintings can be classified into damage restoration, which is intended to restore these works in such a manner that the damaged portions thereof such as worm holes, cracks, breakage holes or holes due to aging, cannot be detected or the restored portions can be detected, and an artistic restoration, which is intended to interpolate the damaged portions after restoration or without restoring them. By interpolating, it is meant that the damage to writing and color on the work is repaired by supplying the necessary painting and drawing in the damaged portions.
In any of the above cases, the purpose of the restoration is to preserve for posterity the historical, artistic, religious and practical impressions and touches of precious paintings and calligraphic works left by our forebears. The need for restoring their damaged portions is extremely great, not only in Japan, but also in other countries in the world, whether the works were made of Japanese paper or machine-made paper.
Conventionally, as a general means for restoring paper paintings and calligraphic works which have been damaged into the depth of their basic materials, a method that occurs to everybody is one using a backing means, such method being frequently employed for restoring paper paintings and calligraphic works.
However, each paper painting and calligraphic work restored by the backing means becomes thicker when it is restored, since the restored portion would have a laminated structure of two sheets of paper, however thin the backing material is.
Further, due to the fact that the surface of the damaged portion becomes raised by an amount corresponding to the thickness of the paper work to be restored, the shape of the restored portion becomes different from the original shape of the work.
Accordingly, the restored work cannot have a thickness equal to its original thickness even when it is bound like a picture album and further, the restored work tends to be damaged on the raised portion at an early stage so that its durability and handling are not satisfactory.
Further, where the paintings and calligraphic works to be restored (hereinafter referred to as the target paper works) are made of acid paper, the oxidation and aging of the damaged portion cannot be prevented even when that portion is repaired and restored by the backing means, so that subsequent restoration is necessary again soon thereafter.
Thus, where a re-restoration and a subsequent re-restoration are made, the restored portion becomes thicker and thicker unless the old backing paper is peeled, which results in the necessity of peeling the backing paper at every restoration.
Moreover, in the case where the backing paper is peeled, due to the fact that when the target paper work is made of Japanese paper consisting of intertwined fibers, those fibers which project beard-like into the damaged portion are bonded to the backing paper, and also due to the fact that the target paper work made of machine-made paper is fragile because it consists of fibers that are not as much intertwined, it is extremely difficult to peel the backing paper from the target paper work without damaging it, unless this is done by a person with great experience and a high degree of skill.
In addition, the repetition of such restoration process is not preferable because it reduces the qualitative values of paper paintings and calligraphic works as cultural inheritances and especially, it also reduces the value of restoration by half since it cannot prevent color change taking place with the passage of time, which results from the degree of aging of paper paintings and calligraphic works.
In order to solve the above-mentioned problems relating to the restoration method using a backing means, a process of uniformly filling restoration fibers into the damaged portion is being used, although somewhat unsatisfactorily, for Japanese paper paintings and calligraphic works. For machine-made paper paintings and calligraphic works, restoration by the backing means is now used conventionally.
The filling process used for restoration of Japanese paper paintings and calligraphic works is a method in which the target paper work is held stationary on a filtering sheet-like member, fibers are filled into the damaged portion of the target paper work by conventional paper hand-making technique so that the filled fibers are fitted to the damaged portion, and after dewatering, the target paper work is removed from the filtering sheet-like member for drying, and after lightly pressing it, the fiber-filled portion is cut to the original size of the damaged portion. Since the strength of the restored portion cannot be provided by the filling of the fibers, the restored portion is further backed for reinforcement.
However, when the portion restored by the above-mentioned filling means is backed, although it is possible to avoid having the damaged portion being raised by the thickness of the paper, which has been the problem involved in the restoration process merely using the backing paper, an increase in the thickness of the damaged portion due to backing cannot be avoided, so that it is not possible to eliminate various problems resulting from the use of the above-mentioned backing means.
Further, where the target paper work on the filtering sheet-like member is removed at the stage after dewatering, the target paper work frequently breaks even if it is deliberately and carefully handled, resulting in a reduction of the precious value thereof. In order to prevent such drawback, an extremely high level of skill is required and a quick restoration operation cannot be expected, resulting in an increase of the restoration costs.
Further, there have arisen a lot of problems in that the color change with time of the restored target printing or calligraphic work due to oxidation, degree of aging and the like cannot be prevented, and at the same time, the durability of the work after restoration cannot be maintained because of an acceleration of the weakening of the work due to oxidation, so that not only sufficient care is required for handling and storage of the restored work, but also another restoration soon becomes necessary.